The accumulation of fluoride by leaves of woody plants growing in the area of sanitary protection zones in the industrial region of Zaporizhzhya

Abstract Vegetation serves as a universal filter that is capable of protecting the environment from pollution by industrial emissions given the availability of appropriate technical facilities. The aim of this study is to determine the ability of leaves of various species of woody plants growing in the area of sanitary protection zones to accumulate fluorine and to establish the most informative indicators of environmental pollution by its compounds. The object of the study was the species of woody plants growing in the area of protective plantations of a number of enterprises of Zaporizhzhya: Zaporizhzhya Titanium & Magnesium Combine, Zaporizhzhya Aluminium Plant PJSC, Zaporizhzhya Abrasive Plant PJSC, Zaporizhstal PJSC, ‘Zaporizhcoke’ PJSC (KOKS), Zaporizhzhya Ferroalloy Plant PJSC, Zaporizhvohnetryv (‘Vohnetryv’) PJSC, PrJSC ‘Ukrgrafit’ and Zaporizhtransformator PJSC. Under the conditions of sanitary protection zones of enterprises the leaves of woody plants accumulate significantly more fluoride compared to the control specimens. We have established that a gradual accumulation of the element occurs during the vegetation period being the most intense in young leaves. In senescent leaves, the activity of its accumulation begins to diminish. The maximum amount of fluoride was detected by us at the end of the vegetation period. Its highest concentration was found in the leaves of woody plants growing in the forest belt near the Zaporizhzhya Aluminium Plant. According to the level of accumulation of the said phytotoxicant in the leaves of plants growing in the area of sanitary protection zones, industrial enterprises of Zaporizhzhya may be ranked as follows: Zaporizhzhya Aluminium Plant PJSC > Zaporizhzhya Ferroalloy Plant PJSC ≥ ‘Zaporizhcoke’ PJSC > Zaporizhstal PJSC > Zaporizhvohnetryv (‘Vohnetryv’) PJSC > ‘Ukrgrafit’ PJSC> Zaporizhzhya Abrasive Plant PJSC > Zaporizhzhya Titanium & Magnesium Combine > Zaporizhtransformator PJSC. The largest amount of fluorine accumulated by the leaves can be attributed to such tree species as: Catalpa bignonioides, Ailanthus altissima, Acer platanoides, Populus nigra, Armeniaca vulgaris, Tilia cordata, Acer pseudoplatanus, Platanus orientalis, which is a distinguishing characteristic of the sanitary protection zones of various enterprises in the city of Zaporizhzhya. Variations of fluorine accumulation in different experimental plots for the same species of woody plants are expressed in quantitative terms. These plants are capable of being the most efficient at purifying the atmospheric air from gaseous fluoride compounds. The highest coefficient of relative accumulation of fluorine in the leaves is found in the following species of woody plants: Catalpa bignonioides, Ailan-thus altissima, Acer platanoides, Populus nigra, Armeniaca vulgaris, Tilia cordata, Acer pseudoplatanus, Platanus orientalis, thus they have a potential to be considered for use as phytoindicators of environmental pollution by the fluorine compounds. The aforementioned coefficient appears to be the lowest in the following species: Morus alba, Elaeagnus angustifolia, Juglans regia and Fraxinus lanceolata.